Image segmentation of hematocyte is a practice of computer medical detection which is based on the medical characteristics of hematocyte, the Computer Graphics, and Image Segmentation. In this paper, we have proposed anew color components' exchanging method on different color spaces for image segmentation. First, extract the color components of the original image, then exchange the order of color components, and get some new images that is different from the original image. Second, compute those components, and put it be a new component in the color space, and make some new images. Assisted by Otsu threshold segmentation and region segmentation technique, to achieve the target segmentation of hematocyte.